But while time heals wounds and lets new generations live without bitterness and anger, hard won lessons can also be forgotten. It is worth asking whether many current Western leaders weren't dozing off in history class.
Among the complex origins of the conflict, economic and political isolationism after 1918 was clearly a major factor. Countries responded to the distortions produced by WWI by closing their markets, thus worsening the great depression. The United States, the USSR and others refused to take part in the collective security arrangements of the League of Nations, while powers like Britain and France appeased Hitler until it was too late.
After 1945, the development of NATO and the European Community showed that the need for international cooperation to ensure peace and prosperity had been understood. Realizing its own economy depended on a stable Europe, the United States loaned billions to the old world through the Marshall Plan.
It is a pity that half a century on, Western Europeans seem to have forgotten all this. While entry for new members seems ever further away, talk of denying entrants the right to freely work in the Union makes its benefits seem decidedly less sweet.
This flows from rhetoric over the past 10 years which has treated Eastern Europe as a threat rather than an asset. Fair concerns about narcotics, illegal immigrants and pollution coming from the region have degenerated into a fear of the people themselves. It is outright hypocrisy to speak of the EU as an area of free trade when new and poorer members will be barred from competing with their skills.
Of course, most of the work to create democracies and market economies has to be done by Eastern European countries themselves. But if the EU continues to offer vague promises rather than firm action, there is a real danger that some of them will revert to dictatorship or become embroiled in armed conflict, with unpredictable consequences for their neighbors and the West. Its hard to say where this will happen; after all, before it tore itself apart, the former Yugoslavia seemed to be the most progressive of all former Communist countries. Unfortunately, the EU's sluggish and unwilling response to the Balkan conflicts is clear evidence that its leadership thinks in narrow provincial terms rather than having a mature conception of wider common interests.
If the legacy of WWII teaches anything, it is that this is a recipe for future conflicts.